This work attempts to prepare antisera to a specific bladder carcinoma antigen(s) and then to isolate this antigen(s). The initial approach is to prepare antisera to bladder carcinomas, fetal bladder, normal adult bladder and control renal tissue. These antisera will be tested using immunohistologic techniques with both frozen and freeze substituted tissue. Positive sera will be absorbed with normal bladder and various other protein preparations, and control antigens. The absorbed antisera will be retested by the same immunohistologic techniques to establish if tumor specific antisera has been obtained. In later studies bladder carcinoma tissue will be extracted as described for the carcinoma embryonic antigen to establish if a similar or analogous antigen exists for these tumors.